Mojave, CA----Interorbital Systems (IOS) today made public the design of its manned orbital launch vehicle, Neptune, and passed a major milestone by completing the propellant tank construction of its Sea Star MSLV (microsatellite launch vehicle). Sea Star is a subscale version of and testbed for the Neptune six-passenger orbital tourism ship. Both vehicles employ a novel modular, pressure-fed, two-stage-and-a-half-to-orbit configuration. â€œIOS is now one step closer to the flight-test phase, and one step closer to launching its orbital tourism services. The Sea Star launches will flight-test and space-validate many of the rocket system design elements that the follow-on vehicle, Neptune, will use.â€